PIN-FORMED1 polarity in the plant shoot epidermis is insensitive to the polarity of neighboring cells

Abdul Kareem; Neha Bhatia; Carolyn Ohno; Marcus G Heisler

doi:10.1016/j.isci.2022.105062

PIN-FORMED1 polarity in the plant shoot epidermis is insensitive to the polarity of neighboring cells

iScience. 2022 Sep 5;25(10):105062. doi: 10.1016/j.isci.2022.105062. eCollection 2022 Oct 21.

Authors

Abdul Kareem¹, Neha Bhatia², Carolyn Ohno^{1

2}, Marcus G Heisler^{1

2}

Affiliations

¹ School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia.
² European Molecular Biology Laboratory, Heidelberg 69117, Germany.

Abstract

At the Arabidopsis shoot apex, epidermal cells are planar-polarized along an axis marked by the asymmetric localization patterns of several proteins including PIN-FORMED1 (PIN1), which facilitates the directional efflux of the plant hormone auxin to pattern phyllotaxis. While PIN1 polarity is known to be regulated non-cell autonomously via the MONOPTEROS (MP) transcription factor, how this occurs has not been determined. Here, we use mosaic expression of the serine threonine kinase PINOID (PID) to test whether PIN1 polarizes according to the polarity of neighboring cells. Our findings reveal that PIN1 is insensitive to the polarity of PIN1 in neighboring cells arguing against auxin flux or extracellular auxin concentrations acting as a polarity cue, in contrast to previous model proposals.

Keywords: Biological sciences; Plant biology; Plant development; Plant morphology.